Synthesis of an enantiomerically pure building block for the synthesis of hydroporphyrins

Abstract

The enantiomerically pure pyrrolidine diester 4 is a useful building block for the synthesis of chiral hydroporphyrin compounds. Treatment of optically active aromatic amines with bislactone 5 gave pairs of N-alkylated lactam-lactone diastereomers 6 and 8. These diastereomers were separated by MPL chromatography and in the case of 8 they could be debenzylated to yield the enantiomerically pure lactam-lactone 7 and its enantiomer. The (–)-lactam-lactone enantiomer 7 was further transformed into building block 4